Exercise Device And Exercise System

ABSTRACT

The invention relates to an exercise device, comprising a frame, a resistance system; and an engagement element, the engagement element being connected to the resistance system using a first line end and a second line end, wherein the resistance system is configured to provide the resistance to extension of the first line end independently from the resistance to extension of the second line end. The invention also relates to an exercise system comprising two exercise devices according to any one or more of the preceding claims.

FIELD OF THE INVENTION

The invention relates to an exercise device, comprising a frame, a resistance system and an engagement element, the engagement element being connected to the resistance system using a line.

BACKGROUND OF THE INVENTION

An exercise device is known from US 2017/0197106 A1. The known exercise device has a leg and a beam carried by said leg. The device includes two handles, each connected to one of two lines which engage respective ends of the beam. Each line is indirectly connected to a flywheel in order to provide a resistance to extension of the lines. As such, a user can grab the two handles with his/her hands, and pull the lines via the handles against a resistance provided by the flywheel, in order to exercise.

The known exercise device has the disadvantage that it is difficult to use for exercising muscle pairs or muscle groups. As an example, arm curl with a dumbell will primarily work the biceps while the triceps remains minimally loaded. A separate exercise movement would be needed to also exercise and balance strength with the tricep, thus resulting in a need to spend more time to exercise both muscles of the muscle pair. Muscle pairs are known to be muscles that perform an opposing movement. Well known examples of such muscle pairs are the biceps and triceps, for respectively bending and straightening the elbow, and hamstrings and quadriceps, for respectively bending and straightening the knee. These are but some examples of muscle pairs and others would be understood by those of skill in the art In order to allow movement of a body part caused by contraction of one muscle in the muscle pair, the other muscle in that muscle pair extends, and vice versa. In the specific example of biceps/triceps, the bicep contracts and the triceps extends to bend the elbow and the reverse will straighten the elbow.

Another exercise device is known from U.S. Pat. No. 5,409,435. It provides a variable resisting force in response to a user applied force. The exercise device includes at least one rotating force transmitting means for inputting a user applied force as a rotational force to be resisted, and at least one force transmission member for transmitting the user applied force. The user applied force is resisted by varying the viscosity of a viscosity variable fluid which surround plates rotated by the user applied force. Thus a braking force is applied to actively resist the user applied force. In accordance with the invention, a multi-configurable multi-programmable exercise device is provided which may be used in a variety of exercise modes to provide a resistive force to a user-applied force during a range of motion of a particular exercise. Disclosed is an embodiment in which a variable resistor resists a user-supplied force in one rotational direction only. A gear and clutch system translates a reciprocating user-supplied force, corresponding to a reciprocating range of motion, into the one rotational direction.

The invention has as an object to solve the problem described above in relation to US 2017/0197106 A1, by providing an exercise device which makes it possible and/or relatively easy to exercise muscle pairs. In particular, the invention aims to allow efficiently and/or effectively exercising muscle pairs.

SUMMARY OF THE INVENTION

The object is achieved by an exercise device of the above described type, wherein the engagement element is connected to the resistance system using a first line end and a second line end, the resistance system providing a resistance to extension of the first line end and the second line end, the first line end engaging the frame at a first engagement mechanism and the second line end engaging the frame at a second engagement mechanism, which is in a different position than the first engagement mechanism, so that a movement of the engagement element with respect to the frame in a first direction from the second engagement mechanism to the first engagement mechanism corresponds to an extension of at least the second line end, and a movement of the engagement element with respect to the frame in a second direction from the first engagement mechanism to the second engagement mechanism corresponds to an extension of at least the first line end, the exercise device thereby allowing reciprocal movement of the engagement element with respect to the frame against the resistance provided by the resistance system, wherein the resistance system is configured to provide the resistance to extension of the first line end independently from the resistance to extension of the second line end.

By attaching the engagement element to the exercise device using two different lines, the exercise device can be used bidirectionally. Because muscle groups in general cause opposing directions, the bidirectionality of the exercise device can be used to exercise both muscle groups in a muscle group at the same time.

It is noted that since the resistance element provides resistance to both line ends extending, resistance is provided in both directions. This is vitally different from existing exercise devices, which provide resistance in one direction only. As a result, using existing exercise device, during an exercise that involves a reciprocating motion, only a single muscle group of a muscle pair is exercised. The single muscle group is exercised both on the leading and the return stroke. In the device according to the invention, different muscle groups of the muscle pair can be exercised in the leading and return stroke, as the resistance is provided in a different direction in each case.

Moreover, by independently providing resistance to the two line ends, the paired muscle groups may be exercised more effectively. As an example, when the resistance experienced by the one muscle group of the pair is not influenced by a (prior) movement of the other muscle group of the pair, the two groups may be trained independently in a single reciprocating exercise.

Moreover, the independent resistance allows using a resistance that is different for one line, and thus for one direction, and the other line. As such, a different resistance can be applied in the first and second direction. Said difference may in particular be advantageous, as muscle pairs exist in which one of the muscle groups needs to be trained more intensively than the other. Using the differing resistance, one muscle group may be subjected to a higher resistance.

The engagement element may be used to engage the exercise device. As such, the engagement element may form an engagement point for a force applied by a user of the exercise device. The engagement element may comprise a handle which can be held by the user.

Alternatively, the engagement element comprises a rod which can be engaged by the user, for instance by grabbing onto the rod or for pushing the rod with e.g. the user's arms, shoulders, legs, etc. The rod may be connected to one or more line ends via joint that allows rotation of the rod with respect to the line, but not translation. An example of a suitable joint is a ball-and-socket joint.

Alternatively yet, the engagement element may comprise a (flexible) loop which can be placed e.g. around said rod or around a body part, such as a leg, of the user. The loop may be made of either one or both of the two line ends.

It is also possible the two line ends each comprise a loop at their end, thereby both forming a separate engagement element. The separate engagement elements may be connected during use. As such, the invention also relates to an exercise device as described in the claims, wherein instead of an engagement element connected to the two line ends, the two line ends each comprise an engagement element that can be connected together via e.g. a fitness implement or a part of a user's body.

The first and second line ends may be ends of the same line or ends of a first line and a second line respectively. The first and second line ends may be part of a single line spanning from the engagement element through the resistance system and back. Alternatively, the single line may span from the resistance system, through the engagement element and back. In the latter case it is also possible the line ends are connected to each other at or near the engagement element, so that in fact the single line is looped, passing the engagement system and the engagement element.

The first and second engagement mechanisms may be integral with or provided on the frame or the resistance system. Furthermore, the first and second engagement mechanisms may each comprise a line guiding element such as a pulley or a block. Alternatively yet, the engagement mechanism may be a part of, or connected to, the resistance system.

According to an embodiment of the exercise device, the resistance system comprises two separate resistance mechanisms, each independently connected to the first line end and the second line end respectively. The resistance mechanisms can thereby each independently provide resistance to extension of the first line end and resistance to extension of the second line end respectively.

According to an embodiment of the exercise device, the resistance system comprises at least two separate resistance mechanisms, each independently connected to the first line end and the second line end respectively. The resistance mechanisms can thereby each independently provide resistance to extension of the first line end and resistance to extension of the second line end respectively. The independent connection of the resistance mechanism may herein be understood as that each resistance mechanism offers resistance only to extension of one line end, but not to extension of the other line end. In case the line ends are part of the same single line, this may be achieved e.g. via a freewheel.

In a further embodiment, the resistance system comprises at least one flywheel for providing the resistance. A flywheel can compactly provide resistance when driven by the first or second line ends upon movement of the grip part in the first or second direction. A flywheel may further provide the advantage that a larger resistance can be experienced by increasing the speed of the exercise. Moreover, the resistance provided by a flywheel is relatively easily adjustable, for instance by providing the flywheel with movable blades, or by engaging the flywheel via a gear system.

The resistance mechanisms may comprise at least two flywheels, for instance one for each resistance element.

Alternatively, a single flywheel could be used. In order to preserve the independent nature of the resistance system when using a single flywheel, various options exist. As an example, the flywheel could be braked, for instance until a complete standstill, when extension of the first line end shifts to extension of the second line end, and vice versa. When fully braked, any movement caused during a prior movement is removed before the next movement commences. As such, the prior movement no long influences the next. The flywheel may rotate in the same direction regardless of which line end is extending. Nevertheless it is also possible for the flywheel to rotate in one direction for extension of the first line end, and in another for extension of the second line end.

The resistance system possibly further comprises a magnetic brake for braking the at least one flywheel. The magnetic brake may resist rotation of the flywheel for the resistance system to provide an additional resistance to extension of the first and second line ends upon the reciprocal movement of the grip part. The magnetic brake may also be configured to brake the flywheel when movement of the engagement element is to reverse, to further separate the resistance to extension of the first line end from the resistance to extension of the second line end by preventing the resistances from counteracting.

When multiple flywheels are used, multiple magnetic brakes may be employed.

In some prior art designs there is a disadvantage in that the momentum generated at the resistance mechanism from one direction of movement will impact the opposite direction of movement. By providing two engagement mechanisms with two separate resistance mechanisms, the effects of such momentum can be reduced or eliminated. In addition, or alternatively, it is possible to instrument the engagement mechanisms and/or their corresponding resistance mechanisms separately and then provide a display of both values. This can be done by e.g. instrumenting the separate resistance element connected with or part of each engagement mechanism/line end. In this manner, the strength of the user in one direction can be measured such that e.g. pushing strength and pulling strength can be measured and displayed separately. In the example of a fluid resistance flywheel, the damper setting of one flywheel can also be adjusted differently than the other flywheel of the pair. In this manner, the speed of the pushing movement and pulling movement could be equal but the work or power output may be different due to the ability to adjust the resistance units. One of skill in the art would appreciate that the available adjustability of different types of resistance can be taken advantage of in a similar way (e.g. magnetic resistance can move the magnet closer/farther from the rotating wheel).

According to a further embodiment, the exercise device further comprises at least one retraction mechanism configured for retracting at least one of the first line end and the second line end. Because the retraction mechanism retracts the one of the first and second line ends when it is not actively extended by a user, superfluous length of line is taken in. The absence of superfluous line length allows the resistance system to provide resistance immediately when extension starts, for instance when reversing the movement of the engagement element. The retraction mechanism may be configured to maintain a minimum tension on the first and/or second line end. It is also contemplated that there may be a different retraction mechanism corresponding with each engagement mechanism/resistance mechanism or line end in that the first line end is retracted by a first retraction mechanism and the second line end is retracted by a second retraction mechanism. In this manner, the retraction movement for each direction of motion is separate from the other one, possibly with the exception that the two are indirectly connected through the engagement element).

In a further embodiment, the exercise device comprises a first line having the first line end and at least one second line having the second line end. The first and second lines may be respectively connected to the two resistance mechanisms.

Using two separate lines may facilitate a relatively simple design of the resistance system. The opposite ends of these first and second lines can be connected to the two separate retraction mechanisms mentioned previously.

According to a further embodiment of the exercise device, the frame comprises at least one leg and a first beam supported by the at least one leg, the first beam carrying at least one of the first and second engagement mechanisms. The first beam may be substantially horizontal, or arranged at a non-zero angle with respect to the leg. The at least one leg may be substantially vertical.

By disposing the engagement mechanism(s) on a beam carried by a leg, an exercise device may be obtained that is versatile in use. The versatility may allow a user to perform a relatively large variety of exercises. Moreover, the beam may aid in positioning the two engagement mechanisms at a distance from each other, which will allow for the reciprocal movement of the engagement element.

The exercise device preferably further comprises a second beam supported by the at least one leg, the second beam carrying the other of the first and second engagement mechanisms. The second beam may be substantially horizontal, or arranged at a non-zero angle with respect to the leg.

By using two beams to carry the engagement mechanisms, an even more versatile design for the exercise device may be obtained. Using two beams is particularly advantageous if the beams are movable with respect to the leg, as will be explained below.

In a further embodiment, the resistance system is at least partly supported by the first and/or second beam.

By supporting the resistance system at least partly by the first and/or second beam, the lines, which are connected to the resistance system, can be kept relatively short. In addition, it is not necessary to move lines to e.g. the leg, which may remove the need for line guides such as pulleys. In other words, a simpler design is facilitated.

Supporting the resistance system at least partly on the beam is especially advantageous for allowing the beam to be movable with respect to the leg, which is a possibility described further below.

It is preferred the first and the second beam each carry one of the first and second resistance mechanisms. Accordingly, lines engaging one beam need not be guided to the other beam. This may allow motion of one beam with respect to the other, which is a possibility described further below.

Preferably, the first beam and/or the second beam are moveable with respect to the leg. Moving the beams with respect to the leg allows moving the position of the engagement mechanisms. As such, different positions for engagement of the lines can be chosen, so as to allow multiple different exercises, and/or to allow users of different sizes to use the exercise device.

In particular, the first beam and/or the second beam may be moveable, preferably together, along a longitudinal direction of the leg. As such, the beam(s) may be height-adjustable. As such, the exercise device may be suitable for persons of different heights. Moreover, the exercise device may be used to perform exercises of the lower body, such as the legs, by setting the beam(s) relatively low, and for exercises of the upper body, such as the beams, by setting the beam relatively high.

It is further preferred that at least one of the first beam and the second beam are rotatable about an axis that is substantially perpendicular to the longitudinal direction of the leg and substantially perpendicular to a longitudinal direction of the respective beam. The beam being rotatable allows the respective engagement mechanism to be positioned at differing heights with respect to each other such that movement of the engagement element in one of the first and second directions is an upward movement and/or movement of the engagement element in the other of the first and second directions is a downward movement. As such, the beams are preferably rotatable with respect to the leg together, in the same rotational direction.

The at least one of the first beam and the second beam is preferably pivotable about an axis that is parallel to the longitudinal direction of the leg. By pivoting the beam about an axis parallel to the longitudinal direction, the first or second engagement mechanism carried by the beam can be moved relative to the other of the first and second engagement mechanisms, thereby adjusting the first and second directions. Furthermore, the first beam and/or the second beam being pivotable about the axis parallel to the longitudinal direction allows the engagement element to be moved closer to and further away from the leg, according to the preference of the user.

The beams may be pivotable independently of each other, or their pivoting may be coupled, for instance mechanically such as by a gear system.

In addition, or as an alternative, the pivoting may allow moving the engagement mechanism away from the leg. As will be explained in relation to the exercise system described below, this allows setting a distance between engagement mechanisms of two exercise devices connected to each other, in order to effectively adjust a width of the exercise system.

According to a further embodiment, the exercise device further comprises a sensor configured for sensing an amount of work performed by moving the engagement element.

Sensing an amount of work allows to track a user's performance, for instance in order to display and/or analyze it. Display of the performance may increase motivation, and additionally or alternatively may allow a user to determine if his effort corresponds to the desired level of intensity. Moreover, tracking the amount of work may allow a user to better make fitness related decisions, such as nutrient intake for recovery, cool-down time, and/or how to structure a workout schedule.

The exercise device may further comprise a display configured to display the amount of work. The display may allow providing direct feedback to the user of his/her performance, which may increase motivation. Moreover, displaying the work performed may allow a user to perform an exercise at a desired intensity relatively accurately, and/or to determine his/her fitness level. The ability to instrument separately each direction of movement for the corresponding engagement mechanism or resistance mechanism allows for the further ability to track how balanced or imbalanced a user's strength is for a particular side of the muscle pair.

The invention also relates to an exercise system, comprising two exercise devices according to any one or more of the preceding claims. In this manner, four resistance mechanisms would be provided and the display could tell the user the difference between left/right sides in addition to differences within the muscle pairs of those sides, providing further detail into the user's strengths/weaknesses.

Using two said exercise devices, symmetrical workouts may be performed. In fact, the exercise system allows exercising both beams and both legs at the same time. As a result, the exercise device may be used to simulate or prepare a user for a variety of real-life exercises, such as skiing, running, kicking etc.

The two exercise devices may be attached to each other via their frames. Accordingly, structurally sound exercise system may be obtained.

In particular, the combined frames of the exercise devices may form a frame of the exercise system. The frame of the exercise system may comprise two substantially parallel legs, for instance the legs of the exercise devices, at a distance from each other. The two legs may be connected by a bridging frame part, for instance overhead and/or at their tops. Accordingly, the frame of the exercise system may have a portal-like shape. The portal shape may allow a user to perform exercises approximately between the legs and below the bridging frame part.

The portal shape may have the advantage that it may offer sufficient structural rigidity for performing relatively heavy exercises, and may further or as an alternative offer the advantage that it relatively clearly defines the area belonging to the exercise device. This is particularly advantageous in e.g. gyms, where the clearly defined area may encourage others to keep clear of the exercise device at least when an exercise is (about to be) performed by a user.

The leg of each exercise device, and thus of the exercise system, may be formed by an A-frame. Alternatively or additionally, the leg of each exercise device may be connected to a support structure keeping the leg upright. The support structure may for instance comprise a floor structure around at least the leg. In particular, the floor structure may be disposed between and interconnect legs of the two exercise devices. This may aid in strengthening the exercise system by firstly interconnecting the exercise devices further. Secondly, the floor structure may prevent or hinder the exercise system to topple over. It may be an additional advantage that, as a user stands on the floor structure, he or she adds to the rigidity of the system by keeping the floor structure to the ground.

It is also possible to anchor the exercise device to the ground, for instance at its legs, however it is likely some gyms may prefer a movable exercise device, such as is offered when a floor structure is used.

Finally it is optionally proposed a distance between corresponding engagement mechanisms of the two exercise devices of the exercise system is adjustable. Effectively, this may allow adjusting the width of the exercise system.

Adjusting the width allows employing the exercise system for users of different sizes, and/or may allow a larger variety of exercises to be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

The exercise device and system are hereafter elucidated with reference to the attached drawings, wherein:

FIGS. 1 and 2 show perspective views of the exercise system including two exercise devices;

FIGS. 3 and 4 shows a side views of one exercise device of FIG. 1 in different positions;

FIG. 5 shows a top view of part of the exercise system;

FIGS. 6-8 show, as a non-limiting example, varying extensions of the first and second line ends connected to respective resistance mechanisms in a side view of the first and second beams; and

FIGS. 9-11 show, as a non-limiting example, varying extensions of the first and second line ends connected to a single resistance mechanism.

DETAILED DESCRIPTION OF THE INVENTION

In FIGS. 1 and 2 an embodiment of the exercise system 100 is shown, comprising two exercise devices 1 and a floor structure 2. The floor structure 2 connects legs 20 of each exercise device 1, which each extending from the floor structure 2. Each exercise device 1 comprises a first beam 21 extending from the leg 20 in a first direction and a second beam 22 extending from the leg 20 in an opposite second direction. The legs 20 of the exercise devices 1 are triangularly shaped and connected at their apexes by a bridging frame part 23 to provide stability to the exercise device 1. Extending from the bridging frame part 23 is a support 24 supporting a display 3 in front of a user standing on the floor structure 2 between the legs 20 and facing the display 3. This display 3 can include software connected to the resistance mechanisms 61, 62 which would calculate accelerations and decelerations of the resistance mechanism 61, 62. By determining the speed of the resistance mechanism 61, 62 and how fast that speed changes, the resistance level of that resistance mechanism 61, 62 can be re-calculated at each time that the resistance mechanism 61, 62 spins without load from the user. Thus by two resistance mechanisms 61, 62 being used, one can spin down and be calculated for drag factor, thus ensuring that the amount of work, force or power output for each resistance mechanism 61, 62 is accurately calculated and displayed. When the user applies force on the next movement, this calculated drag factor or resistance can be used. This is another advantage to providing the two engagement mechanisms 25, 26 and/or resistance mechanisms 61, 62 as described previously.

Each exercise device 1 further comprises a handle 4 to be gripped by the user. Each handle 4 is connected to a first line end 51 engaging the first beam 21 at a first engagement mechanism 25 and to a second line end 52 engaging the second beam 22 at a second engagement mechanism 26. The first engagement mechanism 25 is configured to guide the first line end 51 to a first resistance mechanism 61 supported by the first beam 21 and the second engagement mechanism 26 is configured to guide the second line end 52 to a second resistance mechanism 62 supported by the second beam 22. Movement of the handle 4 in the first direction causes the second resistance mechanism 62 to provide resistance to extension of the second line end 52 and movement of the handle 4 in the second direction causes the first resistance mechanism 61 to provide resistance to extension of the first line end 51. In this case, the resistance mechanisms 61, 62 provide resistance by means of a flywheel rotating in a fluid. Although not shown here, the engagement mechanisms 25, 26 comprise pulleys carried by the beams 21, 22.

In the side view of the exercise system 100 in FIG. 3 , the first beam 21 and the second beam 22 of one of the exercise devices 1 in FIGS. 1 and 2 are shown to be moveable with respect to the leg 20. The first beam 21 and the second beam 22 are connected to the leg 20 via an adjustment mechanism 7 that is moveable along a longitudinal direction of the leg 20 (shown in FIG. 2 ) such that the vertical position of the beams 21, 22 and therewith the vertical position of the first engagement mechanism 25, the second engagement mechanism 26, the first resistance mechanism 61 and the second resistance mechanism 62 can be adjusted by a linear translation of the adjustment mechanism 7 along the leg 20. The adjustment mechanism 7 comprises a travelling body 71 that is provided in a groove 27 in the leg 20 and is configured to allow sliding of the travelling body 71 along the groove 27. The handle 4 is depicted in a neutral position, i.e. no extension of the first line end 51 or the second line end 52 is visible.

FIG. 4 shows the first beam 21 and the second beam 22 to be rotatable with respect to the leg 20 via the adjustment mechanism 7 about a rotation axis R (shown in FIG. 2 ) that is perpendicular to the longitudinal direction of the leg 20 and perpendicular to a longitudinal direction of the beamlike beams 21, 22. The adjustment mechanism 7 comprises a rotation body 70 that is rotatable with respect to the travelling body 71 about the rotation axis R. The beams 21, 22 are shown to be rotatable in dependence of one another, but an embodiment can be envisaged wherein the first beam 21 is rotatable independently of the second beam 22 and vice versa.

In FIG. 5 the exercise system 100 is shown from above. Therewith it becomes apparent that the first beam 21 and the second beam 22 in each exercise device 1 are pivotable about an axis P parallel to the longitudinal direction of the respective leg 20. The pivoting is made possible by the adjustment mechanism 7 comprising hinges 72 connecting the first and second beams 21, 22 to the rotation body 70. Pivoting the beams 21, 22 toward the opposite exercise device 1 causes the handle 4 between the beams 21, 22 to move toward the opposite exercise device 1. Similarly, pivoting the beams 21, 22 away from the opposite exercise device 1 causes the handle 4 between the beams 21, 22 to move away from the opposite exercise device 1. This way, the distance between the handles 4 of the respective exercise devices 1 can be adjusted to account for, for instance, a smaller user or a different type of exercise. It is understood that the various adjustments in position of the resistance unit and its parts, including the beams 21, 22 and the engagement mechanisms 25, 26, whether in rotation or translating or combination thereof can be independent of the other side of the machine or resistance unit or that the same can be linked to move in a coordinated fashion. For example, the left side is independently adjustable from the right side from the user's perspective in FIG. 1 in terms of rotation of the beams 21/22, position in/out and position along axis P and height. As another example, rotation of the resistance unit can cause one side to tilt up and the other down.

In FIGS. 6-8 the first resistance mechanism 61 for providing resistance to extension of the first line end 51 and the second resistance mechanism 62 for providing resistance to extension of the second line end 52 are shown in various extensions of the first and second line ends 51, 52. FIG. 6 shows the handle 4 in the neutral position. In FIG. 7 , the handle 4 is moved in the first direction toward the first engagement mechanism 25, thereby extending the second line end 52. Conversely, FIG. 8 shows that the handle 4 is moved in the second direction toward the second engagement mechanism 26, thereby extending the first line end 51.

Similarly, FIGS. 9-11 show a resistance system 160 for providing resistance to extension of a first line end 151 and a second line end 152 in various extensions of the first and second line ends 151, 152. FIG. 9 shows a handle 104 in the neutral position. In FIG. 10 , the handle 104 is moved in a first direction from a second engagement mechanism 126 toward a first engagement mechanism 125, thereby extending the second line end 152. Conversely, FIG. 11 shows that the handle 104 is moved in a second direction from the first engagement mechanism 125 toward the second engagement mechanism 126, thereby extending the first line end 151. The resistance system 160 comprises one flywheel for providing the resistance and a magnetic brake 164 for braking the flywheel.

The above description of the attached drawings is provided merely for illustrative purposes to contribute to comprehension of the present invention, and is not intended to limit the scope of the appended claims in any way or form. 

1. An exercise device, comprising: a frame; a resistance system; and an engagement element, the engagement element being connected to the resistance system using a first line end and a second line end, the resistance system providing a resistance to extension of the first line end and the second line end, the first line end engaging the frame at a first engagement mechanism and the second line end engaging the frame at a second engagement mechanism, which is in a different position than the first engagement mechanism, so that a movement of the engagement element with respect to the frame in a first direction from the second engagement mechanism to the first engagement mechanism corresponds to an extension of at least the second line end, and a movement of the engagement element with respect to the frame in a second direction from the first engagement mechanism to the second engagement mechanism corresponds to an extension of at least the first line end, the exercise device thereby allowing reciprocal movement of the engagement element with respect to the frame against the resistance provided by the resistance system, wherein the resistance system is configured to provide the resistance to extension of the first line end independently from the resistance to extension of the second line end.
 2. The exercise device according to claim 1, wherein the resistance system comprises at least two separate resistance mechanisms, each independently connected to the first line end and the second line end respectively.
 3. The exercise device according to claim 1, the resistance system comprising at least one flywheel for providing the resistance, possibly further comprising a magnetic brake for braking the flywheel.
 4. The exercise device according to claim 1, further comprising at least one retraction mechanism configured for retracting the first line end and/or the second line end.
 5. The exercise device according to claim 1, comprising a first line having the first line end and at least one second line having the second line end.
 6. The exercise device according claim 1, the frame comprising at least one leg and a first beam supported by the at least one leg, the first beam carrying at least one of the first and second engagement mechanisms.
 7. The exercise device according to claim 6, further comprising a second beam supported by the at least one leg, the second beam carrying the other of the first and second engagement mechanisms.
 8. The exercise device according to claim 6, the resistance system being at least partly supported by the first and/or second beam.
 9. The exercise device according to claim 2, wherein the first and the second beam each carry one of the first and second resistance mechanisms.
 10. The exercise device according claim 6, the first beam and/or the second beam being moveable with respect to the leg.
 11. The exercise device according to claim 10 wherein the first beam and/or the second beam being moveable along a longitudinal direction of the leg.
 12. The exercise device according to claim 10, the first beam and/or the second beam being rotatable about an axis that is substantially perpendicular to a or the longitudinal direction of the leg and substantially perpendicular to a longitudinal direction of the respective beam.
 13. The exercise device according to claim 10, the first beam and/or the second beam being pivotable about an axis that is parallel to a or the longitudinal direction of the leg.
 14. The exercise device according to claim 1, further comprising a sensor configured for sensing an amount of work performed by moving the engagement element.
 15. The exercise device according to claim 14 further comprising a display configured to display the amount of work.
 16. The exercise system, comprising two exercise devices according to claim
 1. 17. The exercise system according to claim 16 wherein the two exercise devices being attached to each other via their frames.
 18. The exercise system according to claim 16, wherein a distance between corresponding engagement mechanisms of the two exercise devices is adjustable. 